Hydraulic mechanisms having biased vanes and balanced end members



A 9, 1966 A. FEROY I HYDRAULIC MECHANISMS HAVING BIASED VANES AND BALANCED END MEMBERS Filed Nov. 9, 1964 w INVENTOR.

ARA E FERm BY ffif A TTORNEYS United States Patent 3,265,006 HYDRAULIC MECHANISMS HAG BIASED VANES AND BALANCED END MEMBERS Arne Feroy, 20017 42nd 8., Kent, Wash. Filed Nov. 9, 1964, Ser. No. 409,822 14 Claims. (Cl. 103-136) The present invention relates to improvements in bydraulic mechanisms of the type disclosed by my prior United States Patent No. 2,929,365, issued March 22, 1960, and entitled Fluid Motors, and in my copending United States application, Serial No. 201,607, filed June 11, 1963, now Patent No. 3,204,566, and entitled Vane Type Hydraulic Mechanism with Balanced Stator Walls.

Reference is made to my said copending application Serial No. 201,607 for a discussion of the problem of leakage at the rotor faces, the causes of such problem, several prior art suggestions to its solution which have proven to be unsatisfactory, and a simple, yet effective solution to the problem, constituting the invention to which such copending application is directed. In part, the present invention also relates to a simple and effective manner of preventing leakage at the faces of the rotor. Simply stated, it comprises making the end members of the stator housing of a one-piece, integral construction, so as to give them inherent rigidity; forming a balancing fluid chamber between the outboard surface of the central portion of each such end member, and a corresponding central portion of an end plate situated adjacent said end member; and directing some of the systems high pressure fluid into each of the balancing chambers, so that such fluid presses inwardly against the end members and counters the forces tending to buckle them outwardly.

According to the present invention, a fluid manifold is formed in each end member, and a fluid flow path is established between each such manifold and each of the balancing fluid chambers. A check valve is located in each of the fluid flow paths and is arranged so that it will open in response to the tendency of fluid to flow into the balancing chambers, and will close in response to the tendency of the fluid to flow out from such chambers. Owing to this arrangement, the high pressure fluid can flow into the balancing fluid chambers from the high pressure manifold, but cannot flow out from said chambers into the low pressure manifold.

Fluid mechanisms of the present invention are operable either as pumps or motors. In my aforementioned United States Patent No. 2,929,365, I disclose using arcuate push rods for urging the vanes into contact with the cam surface of the cam ring when the mechanism is being operated as a motor. In such patent, the push rods are disclosed as being located at the mid-point of the rotor. This necessitates splitting the rotor and then putting it back together again with bolts. According to the present invention, the rotor is of a one-piece construction and the push rods are inset into its side planes or side faces. In this arrangement, alternate ones of each set of push rods cross over the intermediate push rods of the set. The intermediate push rods are set into deeper grooves than the alternate push rods, and the outer faces of the alternate push rods are made to extend substantially flush with the side faces of the rotor.

Also, according to the invention, a seal plug, preferably cylindrical in the shape, is provided at each location where one push rod crosses another. Further, a cushioning spring may extend below and along substantially the full length of each vane to be pushed upon in its end portions by the ends of the push mods associated with such vane.

A still further object of this invention is to provide a hydraulic mechanism of the above described character "ice which is of simple construction and thus may be economically manufactured, is efficient in operation throughout the full range of operating pressures, and is reversible, regardless of whether it is being operated as a pump or a motor.

These and other objects, features, and advantages of the present invention will be apparent from the following description, appended claims, and annexed drawings.

Referring to the drawings wherein like reference characters designate like parts throughout the several views:

FIG. 1 is a view in longitudinal section of a vane type hydraulic mechanism incorporating side plane located push rods, end member balancing fluid chambers, and check valves containing fluid flow paths, according to the present invention, such view being taken substantially along line 11 of FIG. 3;

FIG. 2 is a view in transverse section of the mechanism shown by FIG. 1, taken in the plane of one side surface or face of the rotor, substantially along line 22 of FIG. 1, such view showing the relative arrangement of one of the sets of arcuate push rods;

FIG. 3 is a view in transverse section of the mechanism of FIGS. 1 and 2, taken through one of the end members, substantially along line 3-3 of FIG. 1, such view showing the interior of the fluid manifold in such end member;

FIG. 4 is a view in lateral section of FIGS. 1-3, taken in the plane of the outboard surface of the end member in FIG. 3, substantially along line 44 of FIG. 1;

FIG. 5 is an enlarged view of an upper central portion of the view of FIG. 1, showing one of the vanes and por tions of the push rods and cushion spring associated with it;

FIG. 6 is an enlarged scale, fragmentary perspective view taken toward the region whereat one of two adjacent push rods crosses the other, such view clearly illustrating the difference in depth of the respective grooves for such push rods, and the seal plug provided at such region; and

FIG. 7 is a fragmentary view looking parallel to the plane of the seal member, showing its position relative to the two adjacent push rods, and also showing the relative depth of cut of the grooves for the push rods, with said seal member being shown in section and the outboard push rod in elevation.

FIG. 1 shows a typical hydraulic mechanism accord ing to the present invention. It is illustrated as including a stator or housing 10 and a rotor 12 mounted for retation within the stator 10.

The stator 10 comprises a pair of axially spaced, paral- -lel end members or sections 14, 16 and a cam ring 18, positioned between them. End plates 20, 22 are positioned outboardly of the end members 14, 16. The end members 14, 16 and the end plates or caps 20, 22 are preferably secured to the cam ring 18 by a circular array of bolts, some of which are designated 24.

The cam ring 18 is conventional per se, and includes an inwardly directed, generally oval cam surface. As is illustrate-d, in the side regions the curvature of the cam surface substantially coincides with that of the rotor 12. In the upper and lower regions the curvature of the cam surface is sharper than the curvature of the rotor 12, resulting in the formation of two radially opposed, generally crescent-shaped working chambers 26, 28.

The rotor 12 is provided with a plurality of radial slots 30 spaced around its periphery, and each of such radial slots 30 is provided with a reciprocating vane 32. The reciprocating vanes 32 serve to divide the working chambers 26, 28 into a plurality of compartments whose volumes first increase and then decrease as the vanes 32 sweep through the working chambers 26, 28 during an operation cycle. The reciprocating vanes 32 are in sliding and sealing engagement at their ends with the inner surfaces of the inboard wall portions 34, 36 of the end members 14, 16, and at their outer edges (radial direction) with the cam surface of the cam ring 18.

A generally toroidal or annular shaped fluid manifold is formed in each of the end members 14, 16. For descriptive purposes, the fluid manifold formed in stator plate 14 is termed the inlet manifold and is designated 38, and the fluid manifold formed Within end member 16 is termed the outlet manifold and is designated 40.

End member 14 includes in addition to the inboard wall 36, a generally cylindrical rim portion 42, a generally cylindrical hub portion 44, and an outboard wall 46. As is illustrated, the inboard wall 34 and the outboard wall 46 interconnect between the rim and hub portions 42, 44 respectively. In similar fashion, end member 16 is provided with a generally cylindrical rim portion 48, a generally cylindrical hub portion 50, and an outboard Wall 52. Each end member 14, 16 is of one piece construction and each portion thereof is an integral part of the adjoining portion.

Inlet manifold 38 communicates with a source of hydraulic fluid by way of inlet passageway 54 (FIG. 1) and with the working chambers 26, 28 by way of kidneyshaped inlet valve ports 56 provided axially through inboard wall 34. At the opposite end of the rotor, the working chambers 26, 28 communicate with the outlet manifold 40 by way of kidney-shaped outlet valve ports 58 formed axially through inboard wall 36. The outlet manifold 40 in turn communicates with a point of use or discharge by means of an outlet passageway 60' (FIG. 3). The rotor 12 is spline connected to a shaft 62 which is mounted for rotation by means of bearings 64, 66 positioned inside of the cylindrical hub portions 44, 50, respectively. A seal 68 surrounds the shaft 62 where it leaves an opening in end plate 22.

The alignment of the valve ports is such that the inlet valve ports 58 with respect to the direction of rotation and, of course, are the first to communicate with a given compartment as the rotor 12 rotates. FIGS. 2 and 3 illustrate the relative alignment of the inlet valve ports 56 and the outlet valve ports 58.

Considering the operation of the mechanism as it has been described so far, and assuming that the mechanism is operating as a motor, hydraulic fluid under pressure is delivered through inlet 54 into the inlet manifold 38, completely filling the same. From the inlet manifold 38, the high pressure fluid flow through the inlet valve ports 56 into the compartments formed between the vanes 32 and by the surrounding interior walls of the working chambers 26, 28. The fluid completely fills such compartments and exerts a pressure on their interior surfaces. The remaining compartments are in communication with the outlet manifold 40 which is at a relatively lower pressure. The pressures acting on the two sides of the vanes 32 are not equal but rather are unbalanced. This creates tangential forces which cause rotation of the rotor 12 and the shaft 62 to which it is connected.

In the regions of the compartments containing the high pressure fluid, the pressures acting on the two sides of the stator wall 36 are also not balanced. The high pressure fluid in such compartments exerts an outwardly directed force on the Wall 36, which force is unopposed by fluid in outlet manifold 40 because such fluid is at or near atmospheric pressure. The resultant of the outwardly directed forces, hereinafter termed unbalancing" forces,

lies radially inboardly of the rigid connection of wall 36 with rim portion 48, thereby giving such unbalancing forces a moment arm and establishing an unbalancing turning moment in the outward direction about the line of juncture of Wall 36 with cylindrical rim portion 48. If not balanced, the turning moments would cause the wall 36 to bow or deflect outwardly a slight amount, and this in turn would widen the gap or clearance and cause leakage at the side or rotor 12. 1

Referring again to FIG. 1, in accordance with the present invention, the outward deflection of wall 36 is resisted to a large extent by the rigid, integral structure of end member 16 itself. In addition, a pressurized balancing chamber is provided on the outboard side of wall 52 and high pressure fluid is delivered to it such that a balancing force is exerted on end member 16 in the opposite direction to the unbalancing forces. The mean diameter of the balancing chamber 70 is smaller than the diameter of the rotor 12, resulting in the resultant of the balancing force lying inboardly a substantial distance from the resultant of the unbalancing forces. Therefore, the balancing force has a larger moment arm than the unbalancing forces, and a relatively smaller balancing force can balance the moment produced by the larger unbalancing forces. The area of the pressure surface on the outboard side of wall 52 determines the magnitude of the balancing force and is chosen to be of the size required to create a force that will substantially balance the moments tending to bow or deflect the wall 52 outwardly.

Referring to FIGS. 1 and 4, the balancing chamber 70 is shown to be composed of an annular recess formed in the outboard surface of outboard wall 52, relatively closely adjacent the shaft 62, and by the adjacent portion of the inboard surface of end plate 22. A pair of concentric O-rings 72, 74 are provided at the inner and outer boundaries of chamber 70.

A first passageway or port 76 interconnects between chamber 70 and outlet manifold 40. A valve seat is formed on the chamber 70 end of passageway 76, and a ball type check valve 78, or the like is provided in a well situated adjacent the valve seat.

As best shown by FIG. 1, a second passageway or port 80 is provided through a radial projection 81 (FIG. 3) of hub portion 50. It opens at one end into the chamber 70 and at the other end into the rotor chamber in the vicinity of the inner portions (radially considered) of the vane slots 30 below the vanes 32. At the opposite end of the mechanism, such portions of the vane slots 30 are put into communication with the inlet manifold 38 by means of at least one port 82. The chamber 70 end of passageway 80 is also provided with a valve seat, a ball check valve 84, and a well for such ball check valve 84.

In operation, some of the high pressure fluid in inlet manifold 38 flows first through port (or ports) 82, next through the vane slots 30, below the vanes 32, as such portions of the vane slots 30, as in registry with port 82, and then through passageway 80 into the chamber 70. Check valves 78, 84 are arranged so that they will open to allow fluid to flow into but not out of the chamber 70. Consequently, valve 84 is caused to open because passage way 80 is in communication with the inlet manifold 38 containing the high pressure fluid, and valve 78 is caused to close because passageway 76 is in communication with the outlet manifold 40, and such manifold 40 contains the low pressure exhaust fluid. A kidney-shaped groove 86 may be provided in the inboard side of end member 16 so as to enlarge the inlet to passageway 80.

Accordingly, port 82, the lower portions of vane slot 30, groove 86, and passageway 80 altogether define a fluid flow path for conducting the high pressure fluid from the inlet manifold 38 into the annular balancing fluid chamber 70 during operation of the mechanism so that the outboard side of end member 16 is pressurized in the region of chamber 70, and a balancing moment is produced on such end member in opposition to the unbalancing moment created by the aforementioned unbalancing forces in the high pressure compartments. In this manner the unwanted deflection of the stator wall and the accompanying fluid leakage is curtailed to a point where it causes a minimal loss in efliciency, or is completely prevented.

At the opposite end of the mechanism there is also a tendency for end member 14 to deflect outwardly due to the outward pressure on it by the high pressure fluid in the working chambers 26, 28. Therefore, passageways and check valves identical to those just described are associated with end member 14. More specifically, the outboard side of outboard wall 46 is formed to include an annular recess, preferably of the same size and location as the recess formed in wall 52. Such recess forms a balancing fluid chamber 88 with the adjacent portion of the inboard surface of end plate 20. As at the other end of the mechanism, a pair of concentric O-rings 90, 92 are retained between end member 14 and end plate 20 at the inner and outer radial boundaries of the chamber 88. A passageway or port 04 in a radial extension of hub portion 44 connects between the inlet manifold 38 and the balancing fluid chamber 88. As before, the balancing fluid chamber end of passageway 94 is provided with a valve seat, a well, and a ball check valve 96 in such well. A second passageway 93 corresponding to passageway 80 in end member 16, communicates the interior of annular chamber 83 with the rotor chamber in the vicinity of the base portions of the vane slot 30, below the vanes 32. At the opposite end of the rotor a port 100 is provided in wall 36 for the purpose of communicating the portions of vane slots 30 below vanes 32 with the outlet manifold 40.

In operation the high presure fluid in inlet manifold 38 exerts pressure on both the inboard surface of wall 46 and the outboard surface of wall 34. The forces created by such pressures are substantially equal and opposed. However, the high pressure fluid in the high pressure compartments of the working chambers 26, 28 press against and exert outwardly directed forces on wall 34 which would be unbalanced, and would cause the end member 14 to bow or defiect outwardly in its middle if not balanced. According to the present invention, the unbalancing moments created by such unbalancing forces are balanced by fluid pressure in chamber 88 tending to bow or deflect the central portion of end member 14 inwardly. Owing to the arrangement of check valve 96, some of the high pressure fluid in inlet manifold 38 flows through passageway 94, pushes aside the ball 96, and fills up chamber 88. Its exit through passageway 98 is prevented by the check valve means 102 which is arranged to seat in response to a greater pressure acting on its chamber 38 side. its opposite side is in communication with the system low pressure and outlet manifold 40 by way of the fluid path defined by passageway 98, the inner portion of vane slots 30 below the vanes 32, and the port 100.

It is quite obvious that when the mechanism is operated as a pump, the manifold pressures will be reversed, i.e. the pressure of the fluid in manifold 38 is low and the pressure of the fluid in manifold 40 is high. Consequently, when the mechanism is operated as a pump, and the direction of flow remains the same, the operation of the two pairs of check valves 78, 84, and 96, 102, respectively, are reversed. That is, the high pressure fluid enters chamber 70 through passageway 76 and is prevented from leaving through passageway 80 by the check valve 84. The high pressure fluid enters chamber 88 by way of passageway 98 and passageway 04 is closed by the check valve 96.

When the mechanism is to be operated as a motor, push rods or their equivalent should be provided for urging the vanes 32 against the cam surface.

According to the present invention, push rods .are provided at the side planes of the rotor 12. Rotor 12 is of a solid or one-piece construction. Its side surfaces are planar and parallel, and are situated contiguous the respective inner axially considered) surfaces of the inboard walls 34, 36. As best shown by FIG. 2, a view looking toward the right side of rotor 12 (as viewed in d 6) are formed in the side surfaces of the rotor 12. Each groove 104, 106 extends between and interconnects a pair of circumferentially spaced vane slots 30.

As shown by FIGS. 6 and 7, the grooves 104 are substantially deeper than the grooves 106. An arcuate push rod 108 is provided in each groove 104, and an arcuate push rod 110 is provided in each groove 106. Push rods 108, 110 are preferably identical in construction. At each end of the rotor 12, the push rods 108 are all situated in a common plane, and the push rods 110 are also situated in a common but separate plane, located outboardly of the plane in which push rods 108 are located. In the illustrated embodiment of the invention, at each face of rotor 12 there are a total of twelve push rods 108, 110, and each push rod 110 crosses over two push rods 108, and vice versa.

As best shown by FIGS. 6 and 7, a seal plug or element 112 is interposed between the push rods 108, 110 at each region where one of the latter crosses over one of the former. The shape of such plugs 112 may vary, but a cylindrical shape is preferred because it simplifies the manufacture of both the plugs 112 and the corresponding recesses. The diameter of the seal element 112 is substantially larger than the width dimension of the push rods 108, 110. Seal plugs or elements 112 have planar, parallel side surfaces, one of which is in a sliding and sealing engagement with the side surface of a push rod 108. As best illustrated by FIGS. 6 and 7, the side of each plug 112 opposite the push rod 108 it itself grooved at 113 for the reception of push rod 110.

Seal elements 112 are important for the following reasons: The construction of the mechanism is such that any given push rod 108, 110 is always contacting one vane in the high pressure region of a working chamber 26, 28, and another vane in the low pressure region of a working chamber 26, 28. This is apparent from FIG. 2. As previously mentioned, the alternate push rods 108 are located inboardly of push rods 110, and their grooves 104 are substantially deeper than the groves 1116. Thus, the outer portion of each groove 104 provides an easy path through which high pressure fluid may flow. Without the cylindrical seal plugs 112, at each crossing of the push rods 103, 110, the high pressure fluid in the groove 104 would press against the exposed area (equivalent of the cross-section of push rod 110) of the push rod 110,

forcing it away from one of the arcuate side walls of its groove 106 toward and against the other. Asa result,

.endwise movement of the push rod 110' would probably be prevented due to the resulting friction. Also, the increase in clearance created at the side of groove 106 opposite where frictional contact occurs would provide an easy path for leakage into a low pressure region. Any such leakage would affect the volumetric efliciency of the motor or pump. With the cylindrical seal plugs 112, the push rods 108 and 110 are separated slightly, and the high pressure in each deeper groove 104 acts only against the side of a seal plug 112. The force is taken up on the opposite side of such plug 112 by a surface portion of the recess formed in the rotor 12 for such plug 112. At the same time there is no direct crossing of grooves 104 and 106. Thus, the leakage is only a function of the natural clearance of the push rod and groove assembly. The cylindrical plug seal 112 may be made to float in corresponding close tolerance recesses of rotor 12, but preferably it is permanently pressed (or welded) into the recess in rotor 12 after the deeper grooves 108 have been made so that it becomes an integral and permanent part of the rotor 12.

The two inner corners of each vane 32 are cut away (FIG 5), leaving the vanes with car portions 114, 116 at the outer portions of their respective ends. A spring 118 is located below each vane 32. Spring 118 has flat end portions 120, 122, and a slightly bowed central portion 124. As is clearly illustrated, spring 118 is formed to closely follow the inner contour of the vanes 32. The end portions 120, 122 of the springs 118 bear on the respective end surfaces of the push rods 108, 110, and central portion 124 bears on the radial inner surfaces of the vanes 32, thereby forcing the vanes 32 radially outwardly against the cam surface of cam ring 18.

Hydraulic mechanisms constructed according to the present invention are precision machines and require relatively accurate manufacture of components. However, the use of springs 113 makes the length of push rods 108, 110 and the radial placement of arcuate grooves 104, 106 somewhat less critical. Also, even though mechanisms of this type experience very little wear, if some wear of the push rods and grooves does occur, it will be compensated for by the springs 118.

The hydraulic mechanism of this invention is completely reversible whether it be operated as a pump or as a motor, and reversing is accomplished simply by reversing the direction of flow through the mechanism.

Having thus described the invention, it is clear that the objects as stated above have been attained in a simple and practical manner. While a particular embodiment of the invention has been shown and described, it is to be understood that changes may be made in the construction and arrangements of the various parts without departing from the spirit and scope of the invention as expressed in the following claims.

What I claim is:

1. A rotary hydraulic mechanism comprising a stator and a rotor in said stator forming at least one compartmented working chamber therewith, said stator comprising an end member having concentric, generally cylindrical rim and hub portions, and axially spaced inboard and outboard wall portions extending between said rim and hub portions, and forming an annular fluid manifold therewith, said inboard wall extending contiguous a side of said rotor, said mechanism further comprising an end plate abuttingly engaging an axially outboardly facing first part of said outboard wall and forming an annular balancing fluid chamber with an axially outboardly facing second part of said outboard wall, said end member having a fluid passageway in it interconnecting said fluid manifold with said balancing fluid chamber, and valve means in said passageway permitting the flow of fluid from said fluid manifold to said balancing fluid chamber, but preventing fluid flow in the reverse direction.

2. A rotary hydraulic mechanism comprising a stator and a rotor in said stator forming at least one compartmented working chamber therewith, said stator comprising an end member of one-piece integral construction having concentric, generally cylindrical rim and hub portions, and axially spaced inboard and outboard wall portions, said inboard and outboard wall portions extending between said rim and hub portions and forming an annular fluid manifold therewith, said inboard wall having an inboard side situated contiguous a side of said rotor, said mechanism further comprising an end plate abuttingly engaging an axially outboardly facing first part of said outboard wall and forming an annular balancing fluid chamber with an axially outboardly facing second part of said outboard wall, said end member being formed to include a passageway therein interconnecting said fluid manifold with said balancing fluid chamber, and check valve means in said passageway permitting fluid flow from said fluid manifold to said balancing fluid chamber, but preventing fluid flow in the reverse direction, and means communicating the fluid manifold with a high pressure fluid.

3. A rotary hydraulic mechanism of the vane type comprising a stator and a vaned rotor rotatable in a rotor chamber formed in said stator, said rotor having a plurality of radial vane slots formed in its periphery and a vane in each slot, said stator including a cam ring and a pair of axially spaced end members situated on oppo site sides of said cam ring, with said end members, said cam ring and said varied rotor together forming at least one working chamber, each end member being formed to include an annular fluid manifold and fluid passageways communicating said manifold with a portion of the working chamber, said mechanism further comprising an end plate disposed outboardly of each end member, with a balancing fluid chamber being formed between each end member and the adjacent end plate, each end member being formed to include a first passageway communicating its fluid manifold with the balancing fluid chamber formed by it and the adjacent end plate, a second passageway communicating its balancing fluid chamber with the rotor chamber with the vane slots below the vanes, and at least one port communicating its fluid manifold with the vane slots below the vanes and the said second passageway in the other end member, and check valve means in each fluid passageways in each end member arranged to permit flow into but not out from the balancing fluid chambers.

4. A rotary hydraulic mechanism comprising a stator and a rotor in said stator forming at least one compartmented working chamber therewith, said stator comprising an end member having concentric, generally cylindrical rim and hub portions, and axially spaced inboard and outboard wall portions, said inboard and outboard wall portions extending between said rim and hub portions and forming an annular fluid manifold therewith, said inboard wall having an inboard side surface disposed contiguous a side surface of said rotor, said mechanism further comprising an end plate abuttingly engaging an axially outboardly facing part of said outboard wall, said outboard wall being formed to include an annular recess in its outboard side, said recess forming an annular balancing fluid chamber with the adjacent portion of the inboard side of said end plate, and concentric O-rings retained between the end member and the end plate at the radial inner and outer boundaries of said annular balancing fluid chamber, said end member being formed to include a passageway interconnecting said fluid manifold with said balancing fluid chamber, and a check valve in said passageway permitting fluid flow from said fluid manifold to said fluid chamber, but preventing fluid flow in the opposite direction.

5. A rotary hydraulic mechanism comprising a housing and a rotor journaled for rotation in said housing, at least one working chamber being formed between said rotor and portions of said housing, means dividing said working chamber into a plurality of compartments, said rotor being formed to include a plurality of generally axially extending fluid passageways, said housing including a pair of end members, each of which is characterized by a onepiece, integral construction and comprises concentrically related, generally cylindrical rim and hub portions, and annular inboard and outboard walls extending between said rim and hub portions, with the inboard surface of said inboard wall being disposed contiguous a face of the rotor, and with an annular fluid manifold being formed by and in between said rim and hub portions and said inboard and outboard walls, a generally annular plate situated outboardly of the outboard wall of each end member and forming with it an annular balancing fluid chamber, each end member being formed to include a first passage- Way extending between its annular manifold and the annular balancing chamber formed by it and the adjacent end plate, a port communicating its manifold with the passageways in the rotor, and a second passageway communicating the annular balancing chamber formed by it and the adjacent end plate with the manifold of the other end member by way of passageways extending generally axially through said rotor and the port in the other end member, and check valve means in each of said first and second passageways arranged to open in response to fluid tending to flow into said balancing fluid chambers, but closing in response to fluid tending to flow out from said chambers.

6. A hydraulic mechanism according to claim 5, wherein each said annular fluid balancing chamber is formed by an annular recess provided in the outboard surface of the outboard wall of the end member and a generally flat part of the inboard surface of said end plate, and wherein a pair of concentrically related O-rings are retained between each end member and the adjacent reaction plate at the radial inner and outer boundaries of said chamber.

7. A hydraulic mechanism according to claim 5, Wherein at least the greater portion of said annular balancing chamber is situated radially inboardly of said working chamber.

8. In a rotary hydraulic mechanism having a varied rotor with a planar side surface, and vane actuating push rods inset into grooves in said side surface, with alternate push rods and their grooves crossing intermediate push rods and their grooves, and being inset at a greater depth than said intermediate push rods, resulting in an open channel extending outboardly of the alternate push rods to a depth even with the outboard surface of the alternate push rods, with one end of each push rod and its groove communicating with a low pressure region and the other end of such rod and its groove communicating with a high fluid pressure region, the improvement comprising: seal means at each crossing of two push rods and their grooves, said seal means substantially completely blocking each said channel and preventing high pressure fluid therein from communicating with the low pressure region at the channels opposite end, and from communicating with the low pressure region at one end of the intersect-ing push rod, thereby substantially preventing internal leakage.

9. The combination of claim 8, wherein a recess is formed in said rotor at each crossing of two push rods, to a depth substantially even with the outboard surface of the alternate push rod, said recess cutting across said channel, and said seal means comprises a plug element filling each said recess, said plug element having an inboard side surface extending contiguous the outboard surface of the alternate push rod, an outboard surface set substantially flush with the side surface of said rotor, and having a groove formed in its outboard side configured to snugly accommodate the intermediate push rod, with said intermediate push rod extending through said groove.

10. A rotary hydraulic mechanism comprising a stator including a cam ring having an inwardly directed cam surface, a rotor mounted for rotation in said cam ring, said rotor having parallel side surfaces, radially extending vane slots spaced about its periphery, and a plurality of arcuate grooves formed in each of its side surfaces, With a groove extending from the inner portion of each slot, to the inner portion of another of said vane slots, circumferentially removed from it on the same side of the rotor, with alternate grooves crossing intermediate grooves, and being deeper than said intermediate grooves; a vane in each vane slot, said vanes having radial inner and outer edges surfaces, with said outer edge surface contacting said cam surface; an arcuate push rod in each groove, with the push rods in the alternate grooves being located in a first plane, with the push rods in the intermediate grooves being located in a second plane disposed outboardly of the first plane, with the push rods in the intermediate grooves crossing over push rods in the alternate grooves, and with each push rod operably connecting the two vanes that are in the two vane slots which are interconnected by the groove in which such push rod extends, whereby each vane of each pair of operably connected vanes alternately drives and is driven by the other vane of the pair; and a seal plug element at each region where a push rod crosses another, said seal plug element being inset into the side of the rotor at such region, and having planar side surfaces, the inboard one of which extends contiguous the outboard surface of the push rod in the alternate groove, and the outboard one of which extends substantially flush with the side surface of the rotor, with an arcuate groove being formed in said outboard surface of the seal plug element, and with the push rod in the intermediate groove of the rotor extending through said groove in the seal plug element.

11. A rotary hydraulic mechanism according to claim 10, wherein said rotor is formed to include twelve vane slots, and six arcuate grooves are formed in each side of the rotor, each such groove cutting across portions of two other grooves.

12. A rotary hydraulic mechanism according to claim 10, further including a spring element extending axially of the rotor in each vane slot, between the vane and the bottom of the vane slot, said spring elements having end portions contacted by the end surfaces of the push rods associated with the corresponding vane, such spring elements moving radially in and out with the vanes, in the vane slots, and functioning with the push rods to urge the vanes into sealing contact with the cam surface of the cam ring.

13. A rotary hydraulic mechanism comprising a stator including a cam ring having an inwardly directed cam surface; a rotor having parallel side surfaces, a plurality of radially extending vane slots spaced about its periphery, and a plurality of arcuate grooves formed in each of its side surfaces, with an arcuate groove extending from the inner portion of each vane slot to the inner portion of another vane slot, circumferentially removed from it on the same side of the rotor; a vane in each vane slot, said vanes having radial inner and outer edge surfaces, and opposite end portions, with said outer edge surf-ace contacting said cam surface; an arcuate push rod in each groove operably connecting the two vanes that are interconnected by the groove in which such push rod extends, whereby each vane of each pair of operably connected vanes alternately drives and is driven by the other vane of the pair; and a spring element extending axially of the rotor in each vane slot, contiguous the inner edge surface of the vane, said spring elements having end portions contacted by the end surfaces of the push rods associated with the vane, such cushioning spring elements moving radially in and out with the vanes, in the vane slots, and functioning to maintain the contact of the vanes with the cam surface of the cam ring.

14. A rotary hydraulic mechanism according to claim 13, wherein the inner two corners of each vane are cutaway, and the cushioning spring elements each have a slightly bowed intermediate portion extending contiguous the inner edge surface of the vane, intermediate the cutaway corners, and arm portions interconnecting between the intermediate and end portions of the cushioning spring elements, with the end portions of the spring elements being offset radially inwardly from the inner edge surface of the end portions of the vane.

References Cited by the Examiner UNITED STATES PATENTS 3/1960 Feroy 10'3136 9/1965 Feroy 103*136 

1. A ROTARY HYDRAULIC MECHANISM COMPRISING A STATOR AND A ROTOR IN SAID STATOR FORMING AT LEAST ONE COMPARTMENTED WORKING CHAMBER THEREWITH, SAID STATOR COMPRISING AN END MEMBER HAVING CONCENTRIC, GENERALLY CYLINDRICAL RIM AND HUB PORTIONS, AND AXIALLY SPACED INBOARD AND OUTBOARD WALL PORTIONS EXTENDING BETWEEN SAID RIM AND HUB PORTIONS, AND FORMING AN ANNULAR FLUID MANIFOLD THEREWITH, SAID INBOARD WALL EXTENDING CONTIGUOUS A SIDE OF SAID ROTOR, SAID MECHANISM FURTHER COMPRISING AN END PLATE ABUTTINGLY ENGAGING AN AXIALLY OUTBOARDLY FACING FIRST PART OF SAID OUTBOARD WALL AND FORMING AN ANNULAR BALANCING FLUID CHAMBER WITH AN AXIALLY OUTBOARDLY FACING SECOND PART OF SAID OUTBOARD WALL, SAID END MEMBER HAVING A FLUID PASSAGEWAY IN IT INTERCONNECTING SAID FLUID MANIFOLD WITH SAID BALANCING FLUID CHAMBER, AND VALVE MEANS IN SAID PASSAGEWAY PERMITTING THE FLOW OF FLUID FROM SAID FLUID MANIFOLD TO SAID BALANCING FLUID CHAMBER, BUT PREVENTING FLUID FLOW IN THE REVERSE DIRECTION. 